Biocompatible Copper Oxide Nanoparticle Composites from Cellulose and Chitosan: Facile Synthesis, Unique Structure, and Antimicrobial Activity

Copper in various forms has been known to have bactericidal activity. Challenges to its application include preventing mobilization of the copper, to both extend activity and avoid toxicity, and bioincompatibility of many candidate substrates for copper immobilization. Using a simple ionic liquid, butylmethylimmidazolium chloride as the solvent, we developed a facile and green method to synthesize biocompatible composites containing copper oxide nanoparticles (CuONPs) from cellulose (CEL) and chitosan (CS) or CEL and keratin (KER). Spectroscopy and imaging results indicate that CEL, CS, and KER remained chemically intact and were homogeneously distributed in the composites with CuONPs with size of 22 ± 1 nm. Electron paramagnetic resonance (EPR) suggests that some 25% of the EPR-detectable Cu(II) is present as a monomeric species, chemically anchored to the substrate by two or more nitrogen atoms, and, further, adopts a unique spatially oriented conformation when incorporated into the [CEL + CS] composite but not in the [CEL + KER] composite. The remaining 75% of EPR-detectable Cu(II) exhibited extensive spin–spin interactions, consistent with Cu(II) aggregates and Cu(II) on the surface of CuONPs. At higher levels of added copper (\u3e59 nmol/mg), the additional copper was EPR-silent, suggesting an additional phase in larger CuONPs, in which S \u3e 0 spin states are either thermally inaccessible or very fast-relaxing. These data suggest that Cu(II) initially binds substrate via nitrogen atoms, from which CuONPs develop through aggregation of copper. The composites exhibited excellent antimicrobial activity against a wide range of bacteria and fungi, including methicillin-resistant Staphylococcus aureus; vancomycin-resistant Enterococcus; and highly resistant Escherichia coli, Streptococcus agalactiae, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Candida albicans. Expectedly, the antibacterial activity was found to be correlated with the CuONPs content in the composites. More importantly, at CuONP concentration of 35 nmol/mg or lower, bactericidal activity of the composite was complemented by its biocompatibility with human fibroblasts

Comparative evaluation of predicted and measured performance of a 68-cubic meter truncated reverberant noise chamber

The performance of a medium size, truncated reverberation chamber is evaluated in detail. Chamber performance parameters are predicted, using classical acoustic theory, and are compared to results from actual chamber measurements. Discrepancies are discussed in relation to several available empirical corrections developed by other researchers. Of more practical interest is the confirmation of a recent theory stating that the present guide for the ratio of specimen volume to test chamber volume, approximately 10 percent, is overly conservative, and can be increased by a factor of at least 2 and possibly 3. Results and theoretical justification of these findings are presented

Changes In Submersed Macrophytes In Relation To Tidal Storm Surges

We analyzed long-term submersed macrophyte presence-absence data collected from 15 stations in Kings Bay/Crystal River, Florida in relation to three major storm events. The percent occurrence of most species declined immediately after storm events but the recovery pattern after the storm differed among species. Hydrilla (Hydrilla verticillata (L.F.) Royle)and Eurasian watermilfoil (Myriophyllum spicatum L.) exhibited differing recolonization behaviors. Eurasian watermilfoil recolonized quickly after storms but declined in abundance as hydrilla began to increase in abundance. Natural catastrophic events restructure submersed macrophyte communities by eliminating the dominate species, and allowing revegetation and restructuring of communities. Tidal surges may also act to maintain species diversity in the system. In addition, catastrophic events remove dense nuisance plant growth for several years, altering the public's perception of the nuisance plant problem of Kings Bay/Crystal River

Myosin 1a Regulates Osteoblast Differentiation Independent of Intestinal Calcium Transport.

Myosin 1A (Myo1a) is a mechanoenzyme previously thought to be located exclusively in the intestinal epithelium. It is the principle calmodulin-binding protein of the brush border. Based on earlier studies in chickens, we hypothesized that Myo1a facilitates calcium transport across the brush border membrane of the intestinal epithelium, perhaps in association with the calcium channel Trpv6. Working with C2Bbe1 cells, a human intestinal epithelial cell line, we observed that overexpression of Myo1a increased, whereas the antisense construct blocked calcium transport. To further test this hypothesis, we examined mice in which either or both Myo1a and Trpv6 had been deleted. Although the Trpv6-null mice had decreased intestinal calcium transport, the Myo1a-null mouse did not, disproving our original hypothesis, at least in mice. Expecting that a reduction in intestinal calcium transport would result in decreased bone, we examined the skeletons of these mice. To our surprise, we found no decrease in bone in the Trpv6-null mouse, but a substantial decrease in the Myo1a-null mouse. Double deletions were comparable to the Myo1a null. Moreover, Myo1a but not Trpv6 was expressed in osteoblasts. In vitro, the bone marrow stromal cells from the Myo1a-null mice showed normal numbers of colony-forming units but marked decrements in the formation of alkaline phosphatase-positive colonies and mineralized nodules. We conclude that Myo1a regulates osteoblast differentiation independent of its role, if any, in intestinal calcium transport, whereas Trpv6 functions primarily to promote intestinal calcium transport with little influence in osteoblast function

First Experiences Integrating PC Distributed I/O Into Argonne's ATLAS Control System

First Experiences Integrating PC Distributed I/O Into Argonne's ATLAS Control System The roots of ATLAS (Argonne Tandem-Linac Accelerator System) date back to the early 1960s. Located at the Argonne National Laboratory, the accelerator has been designated a National User Facility, which focuses primarily on heavy-ion nuclear physics. Like the accelerator it services, the control system has been in a constant state of evolution. The present real-time portion of the control system is based on the commercial product Vsystem [1]. While Vsystem has always been capable of distributed I/O processing, the latest offering of this product provides for the use of relatively inexpensive PC hardware and software. This paper reviews the status of the ATLAS control system, and describes first experiences with PC distributed I/O.Comment: ICALEPCS 2001 Conference, PSN WEAP027, 3 pages, 1 figur

Determination of MIC and Disk Diffusion Quality Control Guidelines for Meropenem–Vaborbactam, a Novel Carbapenem/Boronic Acid β-Lactamase Inhibitor Combination

Meropenem–vaborbactam is a carbapenem/cyclic boronic acid β-lactamase inhibitor combination primarily active against Gram-negative bacilli, including those harboring class A serine carbapenemases such as Klebsiella pneumoniae carbapenemase (KPC). A Clinical and Laboratory Standards Institute M23-A4 (Tier 2) quality control study established broth microdilution and disk diffusion ranges for reference strains. Two KPC-producing K. pneumoniae ATCC strains are recommended for quality control testing

Effect of Preanalytical Processing of ThinPrep Specimens on Detection of High-Risk Human Papillomavirus by the Aptima HPV Assay

Two important preanalytical protocols performed on liquid-based cytological specimens, namely, automated cytology processing and glacial acetic acid (GAA) treatment, may occur prior to the arrival of specimens in a molecular diagnostics laboratory. Ninety-two ThinPrep vials previously positive for high-risk human papillomavirus (HPV) via the Cervista HPV HR test were preselected and alternated with 92 previously negative ThinPrep vials. The specimen set was processed in a consecutive fashion by an automated cytology processor without fastidious decontamination precautions. Carryover potential was subsequently assessed by performance of the Aptima HPV assay on aliquots from reprocessed ThinPrep vials. All previously negative ThinPrep vials yielded a negative result following routine automated cytology processing, despite close proximity to known-positive ThinPrep vials. In separate experiments, aliquots from 236 ThinPrep vials were forwarded for tandem analysis with and without GAA treatment. Data from GAA- and mock-treated specimens generated by Aptima HPV were compared to correlate data generated by Cervista. A 99.2% concordance of Aptima HPV results from GAA-treated and mock-treated specimens was noted. This result differed from the concordance result derived from Cervista (91.5%; P \u3c 0.0002). Of the initially positive Cervista results, 21.9% reverted to negative following GAA treatment; the correlate value was 2.7% for Aptima HPV (P = 0.01). While deleterious effects of GAA treatment on genomic DNA were noted with Cervista (P = 0.0015), GAA treatment had no significant effects on Aptima HPV specimen signal/cutoff ratios or amplification of internal control RNA (P ≥ 0.07). The validity of an Aptima HPV result is independent of GAA treatment and routine automated cytology processing

Composite Reflective/Absorptive IR-Blocking Filters Embedded in Metamaterial Antireflection Coated Silicon

Infrared (IR) blocking filters are crucial for controlling the radiative loading on cryogenic systems and for optimizing the sensitivity of bolometric detectors in the far-IR. We present a new IR filter approach based on a combination of patterned frequency selective structures on silicon and a thin (50 $\mu \textrm{m}$ thick) absorptive composite based on powdered reststrahlen absorbing materials. For a 300 K blackbody, this combination reflects $\sim$50\% of the incoming light and blocks \textgreater 99.8\% of the total power with negligible thermal gradients and excellent low frequency transmission. This allows for a reduction in the IR thermal loading to negligible levels in a single cold filter. These composite filters are fabricated on silicon substrates which provide excellent thermal transport laterally through the filter and ensure that the entire area of the absorptive filter stays near the bath temperature. A metamaterial antireflection coating cut into these substrates reduces in-band reflections to below 1\%, and the in-band absorption of the powder mix is below 1\% for signal bands below 750 GHz. This type of filter can be directly incorporated into silicon refractive optical elements